Getter for vacuum devices



Patented ,May 3, 1938 UNITED STATES ,PATENT- OFFICE GETTER FOR- VACUUMI DEVICES Daniel s. Gustin; Bloomfield, N. J., assignor, by mesne assignments, to Westinghouse Electric and Manufacturing Company, East Pa., a corporation oi Pennsylvania Pittsburgh,

No Drawing. Original application October 21, i

1932, Serlal No. 638,995.

Divided and this application May 6, 1936, Serial No. 78,169

14 Claims.

This invention relates to the manufacture of vacuum devices and, more particularly, to the evacuation. of incandescent electric lamps, and is a division of my application Serial No, 638,995

filed October 21, 1932, now Patent 2,042,935 dated Mme-2, 1936 and owned by the assignee or the.

present application. I I

The practice of making incandescent electric lamps includes the operation of removing the gas from the bulb which is accomplished by the use of mechanical means, such as vacuum pumps, and in subsequently removing any residual gas by means of'suitable substances termed "getters.

The present invention is directed to an improved near as possible, allof the residual gasp Many substances and combinations of substances have been employed as clean-up agents and-one form of getter which has been successfully used contains 100 parts by weight of cryolite and 13 parts by weight of phosphorus.

When using such a. getter, it is applied in the form 'of a paste or liquid to the filament. when the filament is heated the getter is driven oil. According to the accepted theory, the cryolite is precipitated to the surface of the bulb and remains there to receive particles resulting from the vaporization of the filament. The cryolite presents an irregular serrated surface so that the solid or opaque particles 'are widely distributed and become ineffective in obscuring the light or, in other words, the cryolite prevents blackening of the bulb.

The phosphorus is. in the form of red phos-- phorus-which, when heated, is converted to yellow phosphorus in the form of a vapor.

. employed The ionization converts the yellowphosphorus vapor to red phosphorus which, durvapor is ionized by the electric discharge between the lead wires of the lamp or between the coils of the filament when such type of fllamentis "ing conversion, causes a physical chemical re- This (01. rue-2) completely removed or rendered inefiective if theionization of the phosphorus or other vapor is increased by a more copious supply of electrons.

It is an object of the present invention, therefore to provide a getter capable of promoting ionization.

Another object of the invention is'to provide a getter containing a thermionlcally active material to promote the clean-up action-of the getter. A further object of the invention is to improve the vacuum in a sealed envelope by providing a substance for increasingthe ionization of a vaporized constituent of a getter.

Other objects and advantages of'the invention ,will be apparent from the following description. When practicing the present invention I have found that good results are obtained by using getter composed of 100 parts by weight of cryolite and 13 parts by weight of phosphorus to which may be added 1.3% or less of a thermionically active substance such as barium carbonate.

These substances may be thoroughly mixed with a binder of nitrocelluluose to provide a paste or it may be in liquid form so that the getter maybe sprayed onto a filament. I have found that the barium oxide resulting from the heating increases the electron emissivity and the carbon dioxide ample, as strontium, or the oxides or compounds of these substances may be used. Furthermore, the material for increasing or promoting ionization may be used with other getter materials in which ionization is effective to clean up residual gases. As an alternative of the above getter composition, I may use inorganic halogen compounds such as iluorlds or double fluorids or sodium chlorid and similar halogen compounds. By adding to such getters a substance such as barium or other substances to promote electron emission, the resultant ionization improves the vacuum by the removal of the residual gas.

- By reason of the present invention a clean-up agent or getter is provided wherein the thermionically active material is a part ofthe mixture used. In the case of a cryolite phosphorus getter, for example, the cryolite periorms its function as does the phosphorus while the added substance, by reason oi the more. copious supply of electrons furnished, promotes ionization thus making the clean-up action more complete, resulting in a higher degree of vacuum than had heretofore been possible.

Although a preferred embodiment of the invention is shown and described herein, it is to be understood that modifications may be made without departing from the spirit and scope of the invention as set forth in the appended claims.

I claim:

' 1. A getter for a vacuum device comprising phosphorus and barium oxide.

2. A getter for a vacuum device comprising cryolite, phosphorus and barium oxide.

3. A substance for removing residual gases from a sealed container, said substance comprising phosphorus, cryolite and an alkaline earth metal compound.

4. A substance for removing residual gases from a. sealed container, said substance comprising phosphorus, cryolite and a barium compound.

.5. A getter for a vacuum device comprising phosphorus and a barium compound.

6. A getter for a vacuum device comprising cryolite, a barium compound, and a clean up agent.

7. A getter for a vacuum device comprising cryolite, barium oxide, and a clean up agent.

cryolite, an alkaline earth metal compoimd. and

a clean up agent.

10. A clean-up agent for the residual gas in a sealed container, said agent comprising a substance vaporizable when heated to combine-with said gas and an alkaline earth metal compound for supplying a copious amount of electrons to promote ionization 01' said vapor to improve its clean-up action.

11. A clean-up agent for the residual gas in a sealed container, said agent comprising a substance vaporlzable when heated to combine with said gas and a barium oxide for supplying a copious amount of electrons to promote ionization of said vapor to improve its clean-up action. I 12. A clean-up agent for the residual gas in a sealed container, said agent comprising a substance vaporizable when heated to combine with said gas and a barium compound for supplying a copious amount of electrons to promote ionization of said vapor to improve its clean-up action.

13. A clean-up agent for the residual gas in a. sealed container, said agent comprising phosphorus to combine with said gas and an alkaline earth metal compound for supplying a copious amount of electrons to promote ionization of said phosphorus to improve its clean-up action.

14. A' getter for an incandescent electric lamp comprising an alkaline earth metal compound and a clean-up agent applied to the filament of said lamp for temporarily promoting ionization of said clean-up agent when said filament is flashed. Y DANIEL S. GUSTIN. 

